Collapsible Spiral Stair

ABSTRACT

A spiral stair that can be collapsed allowing the permanent footprint of the stair to be decreased or eliminated. The stair can be constructed of metal or other common material possessing sufficient strength and rigidity for the application. The stair can be constructed with either a fixed center pole along which then individual steps translate vertically or a telescoping center pole that can be collapsed in sections similar to an automatic antenna. The individual steps would be attached to the various sections and when the center pole is collapsed, the steps would be compressed with the pole into a smaller overall space. A stair could also be constructed in similar fashion to current spiral stairs except the stair case as a unit can be translated vertically, preferably the stair would be raised as a unit into an attic.

BRIEF DESCRIPTION OF DRAWINGS

The advantages of the immediate invention are attained by the devices shown by way of illustration in the drawings in which

FIG. 1 is a perspective view of the spiral stair as described in claim 2 comprising a center pole 1, a plurality of steps 2, a helical track 3 that allows sliding attachment of the steps, and a cable 4 in FIG. 4A that serves to attach the steps one to another.

FIG. 2 shows a device as described in claim 3 comprising a center pole 5, a plurality of steps 6 and a plurality of channels 7 along the length of the center pole 5 within which the individual steps are able to translate. In both configurations, it is preferred that an automatic electronic mechanism be adapted to raise and lower the steps.

FIG. 3 is a top view of the stair in FIG. 2. FIG. 3A is a detail view of the channels 7 along the center pole 5. These are only two preferred configurations for the immediate invention.

DETAILED DESCRIPTION

Spiral stairs have the advantage of a smaller footprint than conventional stairs but this invention improves that advantage. Spiral staircases can be made to collapse or retract in a way that further decreases or eliminates the permanent footprint of the stair.

This invention can have various configurations including designs comprising a stationary center pole along which individual steps slide or swing or a telescoping center pole that is collapsed in the vertical dimension when not in use. Other configurations could exist as well such as a design with no center pole where each step is attached to those directly above and below using mechanical linkages. This later design would conceivably be much more complex and likely less stable.

A preferred configuration of the invention is a stationary and fixed center pole having a single track located along the outside of the pole that rotates around the pole as it extends along the length of the pole. This track serves as the attachment point between the pole and steps; the steps being movable along the track and each step being attached to the step immediately above and below by mechanical means, preferably a metal cable that limits the spacing between steps to a predetermined amount. The uppermost step being fixed permanently or temporarily into position so that each subsequent step would “hang” from the step above.

The preferred material for the invention is metal although other materials such as wood and composites could be used as well. 

1. A spiral stair apparatus comprising individual steps that are not permanently fixed and can be moved either vertically, horizontally, or angularly from their in-use position.
 2. An apparatus as described in claim 1 also comprising a permanently fixed center pole.
 3. An apparatus as described in claim 2 also comprising a center pole having integral longitudinal tracks along which individual steps are allowed to move.
 4. An apparatus as described in claim 2 also comprising a center pole having one track that encircles the center pole as it extends along the length of the pole and serves to facilitate attachment between the center pole and all steps with each step, with the possible exception of the uppermost step, being moveable along the track such that the total of the steps can be raised or lowered with each step being attached to the step immediately above and below by some mechanical means, preferably a metal cable, that would prevent the spacing between steps from exceeding a predetermined limit.
 5. An apparatus as described in claim 2 also comprising a stationary and permanently fixed center pole along which individual steps can translate vertically.
 6. An apparatus as described in claim 2 also comprising a stationary and permanently fixed center pole about which individual steps can be rotated in order decrease the swept area occupied by the spiral stair while not in use.
 7. An apparatus as described in claim 2 also comprising a stationary and permanently fixed center pole and comprising individual steps that are hinged in relation to the center pole in such a way as to allow the individual steps to be folded either up or down so they lay parallel to the center pole when not in use.
 8. An apparatus as described in claim 1 also comprising a telescoping center pole that can be collapsed by some amount when the stair is not in use.
 9. A spiral stair comprising an apparatus that can be retracted and stored in a location or configuration that is different than the location or configuration during use, for example retracting into the ceiling when used as an attic stair.
 10. An apparatus as described in claim 2 also comprising individual steps that are shaped such that the collapsed configuration resembles a pie, creating a new flat surface comprising the individual steps laying within a single plane.
 11. An apparatus comprising a spiral stair made in the common fashion that can be translated vertically, preferably the stair would be used for attic access and raised into said attic as a permanently assembled spiral stair unit when not in use.
 12. An apparatus as described in claim 1 also comprising an automatic electronic or other suitably powered mechanism to raise and lower the individual steps. 